Metering of product in an air cart on hilly terrain

ABSTRACT

An air cart for use in an agricultural air seeding system includes at least one tank for holding a material, and a metering system associated with the at least one tank. The metering system is configured for metering the material from the at least one tank at an output rate. A sensor senses a parameter associated with an angular orientation of the air cart relative to a reference plane, and provides an output signal indicative of the angular orientation. An actuator adjusts an output rate of the metering system. A controller is coupled with each of the actuator and the sensor and receives the output signal from the sensor. The controller is configured for controlling the actuator and thereby adjusting the output rate of the metering system, dependent upon the output signal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to agricultural air seeders, and, moreparticularly, metering systems used in air carts for metering granularmaterial to be applied to a field.

2. Description of the Related Art

Air seeders are commonly towed by a traction unit, e.g., an agriculturaltractor, to apply a product or material such as seed, fertilizer and/orherbicide to a field. An air seeder has as a primary component a wheeledair cart which includes one or more frame-mounted tanks for holdingmaterial. In the case of multiple tanks, the tanks can be separatetanks, or a single tank with internal compartments. The air cart istypically towed in combination with a tilling implement, such as an airdrill, one behind the other, to place the seed and fertilizer under thesurface of the soil. Air seeders generally include a metering system fordispensing material from the tanks and a pneumatic distribution systemfor delivering the material from the tanks to the soil. A centrifugalfan provides at least one airstream which flows through the pneumaticdistribution system. Material is first introduced to the air stream bythe metering system at a primary distribution manifold located below themetering system. The tanks are formed with bottom surfaces that slopedownward at an angle of repose for the granular material toward themetering system. Gravity, in combination with the vibrations andmovement of the air cart, act to move the granular material from theperimeter of the tank toward the metering system located at the centerof the tank. Material is carried by the air stream through distributionlines to a series of secondary distribution manifolds, which in turndistribute the material through distribution lines to seed boots mountedbehind ground openers on the tilling implement so that the product maybe evenly delivered to the ground which is tilled by the tillingimplement.

Metering systems are known for their accuracy on level ground, butbecome inaccurate when operating over hilly terrain. Metering systemscan generally handle an elevation change along the metering length(angle change to the meter axis) but become inaccurate front to back(90° to the meter axis). For example, it is known that a 15° slope onhilly terrain can cause a variation in the output rate of product fromthe metering system of +/−8%. This inaccuracy is due to the change ofthe bottom meter plate relative to the exit point of the product belowthe meter roller. The same type of inaccuracy also occurs with meteringsystems that utilize an auger rather than a roller.

What is needed in the art is an air cart which maintains an accurateoutput rate of product from the metering system, regardless of the slopeof hilly terrain over which the air cart may be operating.

SUMMARY OF THE INVENTION

The present invention provides an air cart which controls an output rateof a metering system, dependent upon a sensed parameter associated withan angular orientation of the air cart (such as on hilly terrain, etc.).

The invention in one form is directed to an air cart for use in anagricultural air seeding system, including at least one tank for holdinga material, and a metering system associated with the at least one tank.The metering system is configured for metering the material from the atleast one tank at an output rate. A sensor senses a parameter associatedwith an angular orientation of the air cart relative to a referenceplane, and provides an output signal indicative of the angularorientation. An actuator adjusts an output rate of the metering system.A controller is coupled with each of the actuator and the sensor andreceives the output signal from the sensor. The controller is configuredfor controlling the actuator and thereby adjusting the output rate ofthe metering system, dependent upon the output signal.

The invention in another form is directed to a metering control systemfor use in an agricultural air cart. The metering control systemincludes a sensor, an actuator and a controller. The sensor senses aparameter associated with an angular orientation of the air cartrelative to a reference plane, and provides an output signal indicativeof the angular orientation. The actuator adjusts an output rate of themetering system. The controller is coupled with the actuator and thesensor and receives the output signal from the sensor. The controller isconfigured for controlling the actuator and thereby adjusting the outputrate of the metering system, dependent upon the output signal.

The invention in yet another form is directed a method of controlling anoutput rate of a metering system for a granular material in anagricultural air cart. The method includes the steps of: sensing aparameter associated with an angular orientation of the air cartrelative to a reference plane; and controlling an actuator to adjust anoutput rate of the metering system, dependent upon the sensed parameter.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1 is a partial, side schematic illustration of an embodiment of anair cart of the present invention;

FIG. 2 is a schematic illustration of an embodiment of a meteringcontrol system of the present invention;

FIG. 3 is a schematic illustration of another embodiment of a meteringcontrol system of the present invention; and

FIG. 4 is a schematic illustration of yet another embodiment of ametering control system of the present invention.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate embodiments of the invention, and such exemplifications arenot to be construed as limiting the scope of the invention in anymanner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIG. 1, there isshown a partial, side schematic illustration of an embodiment of an airseeder 10 of the present invention. Air seeder 10 generally includes anair cart 12 which is towed by a tilling implement 14 (with only aportion of the rear hitch 16 of tilling implement 14 showing in FIG. 1).In the embodiment shown, tilling implement 14 is in the form of an airdrill, but can be differently configured, depending upon theapplication. Air cart 12 may also be configured with a rear hitch (notshown) allowing air cart 12 to be towed in front of, rather than behind,tilling implement 14.

Air cart 12 generally includes a frame 18 which carries steerable frontwheels 20, rear wheels 22, tank 24, blower 26 and auger 28. Tank 24 isillustrated as a multi-compartment tank with internal divider walls (notshown) separating the compartments. In the embodiment shown, tank 24 hasthree compartments 24A, 24B and 24C with each compartment containing amaterial to be deposited into the soil (such as seed, fertilizer,herbicide and/or insecticide). Each compartment 24A, 24B and 24C has atop hatch 30 allowing loading of the material therein.

Air cart 12 includes a pneumatic distribution system 32 for deliveringthe air-entrained material to the trenches in the soil formed by tillingimplement 14. Pneumatic distribution system 32 includes a meteringsystem (not specifically shown in FIG. 1), blower 26 and a plurality ofair lines 36. Air lines 36 extend to and terminate at a convenientlocation for coupling with air lines 38 associated with tillingimplement 14. Air lines 36 are supported at the forward end of air cart12 with a support yoke 40. In the illustrated embodiment, blower 26 is acentrifugal blower, but can be differently configured. Further, in theillustrated embodiment, three primary air lines 36 are shown, one fromeach tank compartment 24A, 24B and 24C. However, the number of air lines36 can vary, depending on the application.

Referring now to FIG. 2, tank 24 is positioned above and connected witha metering system 42 which is configured for metering a granularmaterial M from tank 24 at an output rate. Metering system 42 includes arotatable metering element 44 which rotates at a controlled rotationalspeed about an axis of rotation 46. In the embodiment shown, rotatablemetering element 44 is in the form of a metering roller, but could alsobe configured as an auger for specific applications. Metering roller 44rotates about axis of rotation 46 in a clockwise direction as shown inFIG. 2, as indicated by the curved directional arrow. A plate 48 ispositioned below metering roller 44 at a predetermined spacing andorientation. Plate 48 has a trailing edge 50 from which the granularmaterial falls for entrainment within the airflow from blower 26. Plate48 is shown as a generally flat plate, but could also be curved forspecific applications.

Metering control system 52 includes a sensor 54, actuator 56 andcontroller 58. Sensor 54 senses a parameter associated with an angularorientation θ of air cart 12 relative to a reference plane 60, andprovides an output signal indicative of the angular orientation. In theillustrated embodiment, reference plane 60 is a generally vertical planewhich extends through axis of rotation 46, perpendicular to the drawing.The angular orientation θ corresponds to the orientation of air cart 12on sloped or hilly terrain. As indicated above, a 15° slope on hillyterrain can cause a variation in the output rate of product from themetering system of +/−8%.

Sensor 54 is configured as an inclinometer in the embodiment shown inFIG. 2 and is attached to a generally vertical wall 62. Vertical wall 62is generally parallel to the generally vertical reference plane 60;thus, any tipping of vertical wall 62 caused by hilly terrain likewisecauses and output signal from sensor 54 which is indicative of theangular orientation of air cart 12 relative to vertical reference plane60.

Actuator 56 is connected with plate 48, and adjusts the output rate ofmetering system 42 by controlling the position of plate 48. Moreparticularly, actuator 56 is assumed to be an electric linear actuatorin the embodiment of FIG. 2, with an output shaft 64 which isselectively movable in opposite directions, as indicated by doubleheaded arrow 66. Output shaft 64 is connected at its distal end withplate 48 and likewise moves plate 48 in opposite directions parallel tothe movement of output shaft 64. Moving the trailing edge 50 of plate 48controls the amount of granular material which falls over trailing edge50, and thereby controls the output rate of metering system 42. Actuator56 can be configured as a different type of actuator, such as a fluidactuated cylinder with a piston rod extending from the cylinder.

Controller 58 is coupled with each of actuator 56 and sensor 54 andreceives the output signal(s) from sensor 54. Controller 58 controlsactuator 56 to thereby adjust the output rate of metering system 42,dependent upon the value of the output signal corresponding to theangular orientation θ of air cart 12.

As described above, actuator 56 moves plate 48 in generally oppositelinear directions 66. However, it may also be desirable to configureactuator 56 to move plate 48 in a curved travel path along a radius ofcurvature about axis of rotation 46, as indicated by curved dashed arrow68. This would have the effect of maintaining trailing edge 50 of plate48 at the same position relative to metering roller 44, regardless ofany tipping of tank 24 and metering system 42 relative to verticalreference plane 60.

Referring now to FIG. 3, there is shown another embodiment of a meteringcontrol system 70 of the present invention. Metering control system 70is similar to metering control system 52 in the sense that it controlsan output rate of metering system 72, dependent upon a sensed parameterassociated with an angular orientation of air cart 12. However, meteringcontrol system 70 controls the output rate of metering system 72 in adifferent manner.

More particularly, metering system 72 is pivotally coupled with tank 24at a pivot rod 74. Plate 48 is at a fixed position below and relative tometering roller 44. An actuator 56 is interconnected between tank 24 andmetering system 72, and is movable in opposite axial directions as shownby double headed arrow 76. Controller 58 receives an output signal fromsensor 54 indicative of an angular orientation θ of metering system 72,and controls actuator 56 to move metering system 72 toward and away fromtank 24, as indicated by the adjustable spacing 78.

Referring now to FIG. 4, there is shown yet another embodiment of ametering control system 80 of the present invention. In this embodiment,a metering system 82 is coupled with and immovable relative to tank 24.Tank 24 is carried by and movable relative to frame 18 of air cart 12. Ashock absorber 84 (or more than one shock absorber) interconnects oneside of tank 24 with frame 18, and an actuator 56 (or more than oneactuator) interconnects an opposite side of tank 24 with frame 18. Plate48 is at a fixed position below and relative to metering roller 44.Sensor 86 is in the form of a weight sensor associated with tank 24.Dependent upon the angular orientation of tank 24, the force vectors ofthe weight applied to weight sensor 86 will vary, which in turncorrelates to an angular orientation θ of air cart 12 relative to thevertical reference plane 60. Controller 58 receives an output signalfrom sensor 86 indicative of an angular orientation of tank 24 andmetering system 82, and controls actuator 56 to move tank 24 toward andaway from frame 18, as indicated by the double headed arrow 88. Ratherthan using a weight sensor 86, metering control system 80 may optionallyuse a sensor in the form of an inclinometer 90 (shown in dashed lines)which provides an output signal to controller 58 corresponding to anangular orientation of metering system 82.

While this invention has been described with respect to at least oneembodiment, the present invention can be further modified within thespirit and scope of this disclosure. This application is thereforeintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

What is claimed is:
 1. An air cart for use in an agricultural airseeding system, comprising: at least one tank for holding a material; ametering system associated with said at least one tank, said meteringsystem being configured for metering said material from said at leastone tank at an output rate and including: a rotating metering elementconnected to said at least one tank and rotating in a given direction,said rotatable metering element having an axis of rotation and beingbisected by a generally vertical reference plane extending through saidaxis of rotation; a vertical wall moveable with respect to the referenceplane; and a plate positioned below said rotatable metering element andhaving a trailing edge relative to the direction of rotation of saidrotating metering element; a sensor operatively connected to thevertical wall for sensing a parameter associated with an angularorientation of said vertical wall relative to the reference plane, saidsensor providing an output signal indicative of said angularorientation; an actuator for adjusting said output rate of said meteringsystem by displacing said trailing edge; and a controller coupled witheach of said actuator and said sensor and receiving said output signalfrom said sensor, said controller being configured for controlling saidactuator and thereby adjusting said output rate of said metering system,dependent upon said output signal.
 2. The air cart of claim 1, whereinsaid sensor senses an angular orientation associated with said at leastone tank relative to said reference plane.
 3. The air cart of claim 1,wherein said sensor is an inclinometer.
 4. The air cart of claim 1,wherein said actuator is coupled with and controllably moves said plate.5. The air cart of claim 4, wherein said rotatable metering elementcomprises one of a roller and an auger.
 6. The air cart of claim 5,wherein said actuator controllably moves said plate along a radius ofcurvature about said axis of rotation.